Rotor unit for a postage meter machine

ABSTRACT

A rotor unit comprises a rotor cylinder which is fastened to a shaft and is rotatably supported via an external bearing. A gear motor is arranged in the interior, which gear motor drives a first double gear wheel in both rotating directions (a, b) via its power take-off shaft and a pinion. The double gear wheel is supported on a disk and a bearing plate in a freewheel bearing and engages with a second double gear wheel. In one rotating direction (b), the freewheel bearing locks the toothed wheel, so that the latter, rigidly together with the disk, is carried along by the pinion. In this way, the second double gear wheel engages serially with one intermediate gear in each instance, wherein every such engagement is exactly positioned by means of a ball catch. In the other rotating direction (a), the motor in each instance turns a number wheel via the aforementioned gears and accordingly sets e.g. one digit of the postage meter machine&#39;s value stamp. All digits of the value stamp, date stamp and other stamps are adjusted automatically by means of alternate rotation in the two rotating directions (a, b). The motor receives its commands, via sliding contacts, from a control unit arranged outside the rotor cylinder.

FIELD OF THE INVENTION

The invention is directed to a rotor unit for a postage meter machineand to a method for operating such rotor unit.

BACKGROUND OF THE INVENTION

Postage meter machines are commercially available in a number ofvariations. A printing rotor which comprises a postage value stamp onits cylindrical surface is standard in these machines. The numerals onthis value stamp are selectively movable and are set by the useraccording to the postage required in each case. A counter or meteramount storage, in which all meter amounts and postage amounts are addedup so that they can be accounted for by the authorized postal authority,is coupled with the postage value stamp. In addition, a place and datestamp, an advertizing stamp and possibly other stamps are arranged onthe cylinder surface of the printing rotor and can be set as desired.

In metering, the printing rotor rolls over the postal item to bemetered, e.g. a letter, making a complete revolution and in so doingimprints the various stamps one after the other. Such a postage metermachine is described for example in Hasler Mitteilungen [Hasler Review]37 (Apr. 1978), No. 1, pages 1-7 (R. Grunig: Die Frankiermaschine HaslerMailmaster [The Hasler Mailmaster Postage Meter Machine]).

In the past, the postage value stamp was generally adjusted via toothedracks which are supported in the shaft of the printing rotor so as to bedisplaceable in the longitudinal direction of this shaft and constitutepart of a working connection between the value stamp and the meteramount storage. Patent CH 160 586 is referred to in this regard by wayof example.

A newer postage meter machine is known from U.S. Pat. No. 4,702,164 inwhich the postage amounts are set without the aid of toothed racks ofthe aforementioned type. This postage meter machine has a printing rotorwhich is supported on its shaft so as to be rotatable. The printingrotor and the adjusting means therein can be connected in threedifferent ways by means of a positioning rod, which is displaceable inthe longitudinal direction, and by other means. Accordingly, threedifferent modes of operation can be adjusted. In the "value select" or"digit select" operating mode, a printing wheel is rotated into adesired adjusting position while the rotor remains stationary, therebysetting a number to be imprinted. In the "print wheel select" (bankselect) operating mode, the next print wheel to be set is mechanicallycoupled with the shaft while the rotor again remains stationary.Finally, in the third operating mode, "print", the rotor is rigidlycoupled with the shaft in the conventional sense and the desiredmetering is effected in that the rotor rolls over the postal itemrunning through it.

The shafts of all of the aforementioned postage meter machines arerelatively complicated, and accordingly costly parts which can generallybe produced only by chip-removing machining.

SUMMARY OF THE INVENTION

A primary object of the invention is to provide a postage meter machinein which the shaft of the printing rotor is constructed in a more simplemanner. Further, the remaining construction should be capable of beingmanufactured more easily and, thus, more cheaply.

In accordance with the present invention, there is provided a rotor unitfor a postage-meter machine, comprising a rotatingly mounted rotorcylinder, at least one stamp, located on the rotor cylinder, with whichare associated a number of adjustable number wheels, setting elementswhich can be mechanically coupled to the number wheels and by means ofwhich these wheels can be set according to requirements of a user, adrive shaft that can be rotated in opposite directions and which actstogether with the setting elements, a drive motor which drives the driveshaft either directly or via step-down gearing, locking means which lockagainst movement all numeral wheels whose setting is not to be changedat the particular time, and connecting means which, depending on thedirection of rotation of the setting shaft, act in such a way that whenthe shaft rotates in one direction, the shaft can be coupled with anydesired number wheel, whereas when the shaft rotates in the oppositedirection, a coupled number wheel can be brought into the desiredsetting position.

For a better understanding of the present invention, reference is madeto the following description and accompanying drawings while the scopeof the invention will be pointed out in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example of a stamp imprint;

FIG. 2 illustrates a block diagram of a postage meter machine;

FIG. 3 illustrates a block diagram of a rotor unit;

FIG. 4 is an exploded view of parts inside a printing rotor;

FIG. 5 is a general drawing of the printing rotor in longitudinalsection;

FIG. 6 is a general drawing of the printing rotor in cross section;

FIG. 7 illustrates an alternative to the printing rotor corresponding toFIG. 5;

FIG. 8 illustrates a longitudinal section through a second rotor unit;

FIG. 9 illustrates a longitudinal section through a third rotor unit.

DETAILED DESCRIPTION OF THE INVENTION AND PREFERRED EMBODIMENTS

FIG. 1 shows an example of a stamp imprint by a postage meter machine. Afour-digit amount is indicated in the value stamp 11, in this example,the number 0475, meaning "postage amount 4 guilders, 75 cents". A secondround stamp 13 is imprinted to the left of this, bearing the place nameat the edge and the date 14 on the inside. The third imprint is aninformative text 15 which is contained on an interchangeable printingblock and has no postal significance.

FIG. 2 shows a rough block diagram of a postage meter machine 19. Itcomprises a keyboard and display unit 20, control unit 22, a meteramount storage 24, a rotor unit 25 and a transporting unit 28. Ametering process for the postage, e.g. 4 guilders, 75 cents, is enteredvia the keyboard and display unit 20. The control unit 22 ensures thatthis postage amount is correctly set in the rotor. The control unitfurther controls the transporting of the postal item to be metered, e.g.a letter, to the rotor which rolls over the item passing by it and in sodoing prints the postage amount on it. The metering operation and themeter value or postage amount which is used are stored in the meteramount storage 24 and indicated on the display. The postage amount canalso be input automatically rather than manually, e.g. via a connectedpostal scale with postage calculator.

The meter amount storage (prepayment meter) 24 and rotor unit 25 form aspecially secured combination which ensures that each metered value canalso be accounted for by the authorized authority, in particular thenational postal authority. This is indicated in the drawing by border23.

FIG. 3 is a block diagram of the rotor unit 25 which is composed ofelectrical and mechanical parts. The electrical working connections areindicated by single arrows and the mechanical working connections bydouble arrows. Rotor unit 25 comprises the actual rotor 26 and the unitsarranged outside of this rotor 26.

Rotor 26 comprises a unilaterally and rotatably supported shaft 31 towhich rotor cylinder 33 is centrically flanged. The latter isconsiderably larger in diameter than shaft 31 and contains variousstamps 35 to 38 within it. These stamps are arranged in such a way thattheir curved printing areas 35' to 38' form a part of the cylindricalsurface of the rotor cylinder 33. The stamp 35 is a postage value stampshowing, e.g. the postage amount to four decimal places. This stamp isobligatory for all postage meter machines. The next stamp is a date andplace stamp 36 with an adjustable date. The third stamp is anadvertizing stamp 37 with no postal significance, which can be foldedout of the way and exchanged, and the fourth stamp is a postalidentification stamp 38 for indicating the mailing class, e.g."registered". Stamps 37 and 38 are purely optional and are used at thediscretion of the user of the postage meter machine. Additional stampsare readily conceivable, provided there is sufficient space in the rotorcylinder 33.

An adjusting or setting element 45 to 48 is assigned to each stamp 35 to38. These adjusting elements are either toothed wheels which mesh withthe printing elements of the stamps 35 to 38 (e.g. the number wheels ofthe value stamp 35) or toothed levers, by means of which e.g. theadvertizing stamp 37 can be lowered or raised. Each of the adjustingelements 45 to 48 has a gearing area 55 to 58. These areas are locatedon a common circle whose center 54 does not necessarily lie on thegeometric axis 34 of the rotor cylinder 33.

Further, a small drive motor 62, a clutch arrangement 64, a gearingelement 66, and a bearing element 8 for the latter 66 are arranged inthe rotor cylinder 33. Motor 62 drives either gearing element 66 or itsbearing element 68, as desired, via the clutch arrangement 64. Bearingelement 68 may be designed e.g. as a disk which is rotatably supportedin the center 54 of the circle 53. Motor 62 is supplied with current viacontacts 61.

The following elements of the rotor unit 25 are arranged outside rotor26: an additional drive motor 72 with associated control 73 for drivingthe rotor 26, an additional control 75, current source 77, controlswitch 79, setting sensor 81 and rotation sensor 83. These units serveto control drive motor 62 and to control and monitor the adjustingprocesses in rotor 26.

FIG. 4 shows, as an example of a first concrete embodiment, an explodedview of a portion of the structural component parts of rotor 26 whichare shown schematically in FIG. 3. The cylindrical drive motor 62 has,on its power take-off shaft 63, a pinion 163 in the form of a spur gear.The pinion 163 engages with a first double gear wheel 165 comprising aspur gear 166 and a bevel gear 167. This double gear wheel 165 isrigidly fastened to a shaft 170.

The first double gear wheel 165 engages, via its bevel gear 167, with asecond double gear wheel 175 which is preferably identical to the first(165). This second double gear wheel 175 engages, via its spur gear,with an intermediate gear 179, and the latter 179 in turn engages with anumber wheel 180.

The second double gear wheel 175 is supported in a slot-shaped orpocket-shaped cut out portion of a disk 185 transversely relative to theaxle 170 in such a way that its spur gear just reaches the edge 186 ofthe disk. The edge 186 of this disk 185 is bevelled in a wedge-shapedmanner corresponding to the shape of the teeth of the spur gear of thesecond double gear wheel 175. In this way, one tooth of the toothedwheel 175 aligns in each instance with disk edge 186 without substantialintermediate space, i.e. edge 186, together with the tooth, forms apractically closed circle.

Disk 185 is rigidly held at one end of a hollow shaft 188. A bearingplate 193 is arranged, also rigidly, at the other end of the shaft 188.A freewheel bearing 171, in which shaft 170 is supported, is arranged inbearing plate 193. Due to this type of bearing and assembly, the firstdouble gear wheel 165 is rotatable in one direction only. Finally, thehollow shaft 188 is rotatably supported on a fixed axle 190.

FIG. 5 shows a completed general drawing of rotor 26 in centrallongitudinal section. The rotor cylinder 33 is flange mounted at theunilaterally arranged bearing shaft 31 via bearing area 32. This bearingarea has a medium diameter and is rotatably supported in an externalbearing 132. It contains in its interior the drive motor 62 to which thestep-down gearing 62' and the aforementioned drive shaft 63 are flanged.The motor 62 drives the two double gear wheels 165 and 175, theintermediate gear 179 and number wheel 180 in one rotating direction, a,via the pinion 163. In its other, opposite rotating direction, b, thefirst double gear wheel 165 is locked by the freewheel bearing 171. Asit rotates, the pinion 163 accordingly carries along the disk 185, thebearing plate 193 and the parts supported on the latter. This means thatthe disk 185 in particular is made to rotate around the axle 190 in thesecond direction, b, of rotation.

The elements described with reference to FIGS. 4 and 5 can be mountedfrom the front side 133 of the rotor cylinder 33 and are held by meansof the frontal bearing element 134. Ball catch elements 136 between thebearing element 134 and the bearing plate 193 ensure that the disk 185can be stopped at the correct predetermined angle positions. Disk 185 isarranged in such a way that its bevelled edge engages between two teethof intermediate gear 179 in each instance. In addition, and at the sametime, it must engage correspondingly with the gears and the toothedlevers which constitute the gearing areas 55 to 58 of the adjustingelements 45 to 48 (FIG. 3).

FIG. 6 shows a second general drawing in cross section through the rotorcylinder 33, approximately in the plane of disk 185. Disk 185 iscentrally supported and its bevelled edge 186 engages with the gearingareas of the adjusting (setting) elements 45 to 48 arranged circularlyaround the disk 185. The five number wheels 180 of the postage valuestamp 35, for example, are mentioned as the first of these adjustingelements. The middle one of these wheels 180 is presently engaged, viaits assigned intermediate gear, with the second double gear wheel 175.The other adjusting elements shown are the date stamp 36 with fiveadjustable date number wheels 181, the advertizing stamp 37, which canbe lowered, and the postal identification stamp 38.

The number wheels 180 of the postage value stamp 35 with their printingareas, indicated in black, lie along the outer circumference of therotor cylinder 33. Since their own dimensions are uniform, they cannotbe mounted on a common, linear axis (as shown in FIG. 6). This axis mustrather be curved or have steps corresponding to the required curvature.In addition, it is necessary to ensure that the gearing areas of numberwheels 180 cooperate with the outer circle or edge 186 of the disk 185.This can be achieved by means of helical gearing. The same naturallyalso applies in a corresponding manner to the number wheels 181 of thedate stamp 36.

The arrangement described thus far operates as follows: Prior to use,the rotor 26 and the disk 185 are in their starting positions and thenumber wheels 180 of the postage value stamp 35 are at zero. As soon asa letter is to be stamped, the user of the postage meter machine 19enters the required postage amount into the machine via the keyboard 20.This amount, e.g. 4 guilders, 75 cents, appears in the control unit 75which, via control switch 79, sets the drive motor in motion in thesecond rotating direction b. When the motor is turning in this rotatingdirection b, double gear wheels 165, 175 are blocked by the freewheelbearing 171 as was described. Consequently, disk 185 turns in aclockwise direction and causes the second double gear wheel 175 toengage with the intermediate gear 179 of the first number wheel 180 ofthe postage value stamp 35, which number wheel 180 is responsible forthe smallest value. When the disk 185 is in this position, the drivemotor 62 reverses direction. This releases the freewheel bearing 171 andthe disk 185 positions itself exactly due to the elastic force of theball catch element 136. The drive motor 62 now rotates in its firstrotating direction a, and in so doing takes with it the two double gearwheels 165, 175 and, via intermediate gear 179, adjusts the number wheel180 to position 5 corresponding to 5 cents.

By briefly reversing the motor 62 into the second rotating direction b,the second double gear wheel 175 engages with the intermediate gear 179of the second number wheel 180 of the postage and value stamp 35 and,with the motor turning in rotating direction a, this number wheel isthen adjusted to position 7, corresponding to 70 cents.

By reversing the motor 62 into the second rotating direction b, thesecond double gear wheel 175 is engaged with the intermediate gear 179of the third number wheel 180 of the postage value stamp 35 and, whenthe direction of rotation is again reversed to direction a, this numberwheel is adjusted to position 4 corresponding to 4 guilders. Thisconcludes the postage setting for value stamp 35 and with the motoragain turning in rotating direction b, disk 185 returns to its startingposition.

During the setting operation, rotation sensor 83 monitors the rotationof motor 62 in the two rotating directions a and b. Parallel to this,the setting sensor 81 monitors the adjustment of the number wheels 180and their final position. The results of the monitoring are continuouslyreported back to control unit 75, so that the latter is constantlyinformed about the execution of its control commands.

As soon as the setting operation has been properly completed, theadjusted postage amount appears on the display of the keyboard anddisplay unit 20 of the postage meter machine. This enables the user toperform a visual check. It also signals that the stamping operation cannow take place, e.g. by introducing the letter to be stamped into thepostage meter machine 19. The rotor control 73 accordingly receives itsstart command, the rotor drive motor 72 begins to rotate and effects asingle, full revolution of the rotor cylinder 33. The printing areas 35'to 38' of the stamps 35 to 38 are inked and roll over the letter,thereby transferring the ink to the letter in the form of a stampimprint. At the same time, the adjusted postage amount of 4 guilders, 75cents is registered in the meter amount storage 24.

By repeating the start command to rotor control 73, the next letter canimmediately be metered with the same postage amount. If on the otherhand a different amount is to be used, number wheels 180 of the postagevalue stamp 35 must be reset to the new amount, analogously to thesetting process described above.

The setting process can only be effected when the rotor 26 is in therest position. This requirement can be satisfied, for example, in thatthe contacts 61 for the power supply to the drive motor 62 are designedin point form, rather than spread out annularly over the entirecircumference of its bearing area 32. In this case, contact will occuronly when the rotor 26 is at the angle corresponding to the restposition.

If the setting of the date stamp 36 is to be changed, the correspondinginput is also effected in this case via the keyboard of the unit 20 andthe control unit 75 controls the disk 185 and the number wheels 181 tothe assigned angle positions in a manner analogous to the processdescribed above for inputting the postage value. The same applies to thelowering or placing-in-position of the advertizing stamp 38 and theother stamps 37. In this case also, the drive motor 62 rotatesalternately in its two rotating directions b and a, thereby bringing thedisk 185 into the desired angle position and accordingly causing thedouble gear wheel 175 to engage with the assigned adjusting element 48or 47. Because of its function, the second double gear wheel 175 canalso be referred to as a coupling gear.

Control unit 75 is preferably designed in such a way that it stores theinformation contained in it such that the information cannot be lost. Inparticular, the information is not lost when the postage meter machine19 is switched off. Data concerning the respective angular position ofthe disk 185 and all number wheels 180, 181, as well as the position ofthe advertizing stamp 38 and other stamps 37, is contained in thecontrol 75 in suitable form as constantly changing information. Itcomprises, e.g., information concerning the number of revolutions ofdrive shaft 63 required to go from every position to every otherposition as permanently stored data.

Rotation sensor 83 is designed, for example, as a clock disk 110 whichis mechanically coupled with the drive motor 62 via an intermediate gear111 (FIG. 5). A light barrier 112, which is formed, e.g., in a U-shapedmanner, scans clock disk 110 in such a way that not only the number ofrevolutions of drive shaft 63 are determined, but also the respectiverotating direction a, b.

Setting sensor 81 also works in a contactless manner, particularlymagnetically. For this purpose, number wheels 180 of the value stamp 35are magnetically coded; at least the zero position is magneticallymarked.

Control switch 79 is a semiconductor switch which allows the drive motor62 to be switched from forward to reverse. If the motor 62 is a DCmotor, this means that the polarity of the current direction must bereversed. If the motor 62 is a step motor, the control switch 79 is acomplicated motor control switch, but one which is known per se.

The embodiment example for a rotor unit 25 described with reference toFIGS. 4 to 6 is based on a general construction principle with thefollowing features:

A drive shaft 63 which can rotate in both rotating directions is locatedin the interior of the rotor 26.

Drive shaft 63 is driven by a motor 62 either directly or via astep-down gearing 62', wherein a control arrangement 75, 79 controls themotor 62.

There is a primary means in the interior of rotor 26 by which driveshaft 63 is mechanically coupled with a single number wheel (e.g. 180)in each instance or with a single gearing area 55-58 in each instance,respectively.

There are secondary means which mechanically couple the drive shaft 63with the respective selected number wheel (e.g. 180) or with theselected gearing area 55 to 58, respectively, in such a way that onesetting, e.g. of a number in the printing position, can be effected.

There are tertiary means which lock all those number wheels or gearingareas 55-58, adjusting elements 45-48 and printing elements 35'-38'which are not being adjusted at that particular time.

The primary and secondary means comprise a clutch arrangement 64 whichcouples the primary or secondary means with the shaft 63, depending onthe direction of rotation a, b of the drive shaft 63.

The tertiary means are centrally symmetrical, preferably in the form ofa disk 185, and are in contact with the primary and secondary means.

The following variants of the actual construction can be derived fromthe preceding general construction principle:

Clutch arrangement 64 was described with reference to FIGS. 4 and 5 as adevice having a (single) freewheel bearing 171. This is a firstembodiment form, however, the clutch arrangement can also be constructedas a self-switching change gear or the like.

FIG. 7 shows a variant of FIG. 5 with two freewheel bearings 172, 173,which is suitable for manufacturing by means of the plastic injectionmolding technique. A support 192 which is symmetrical with respect torotation and comprises disk 185 in the form of a collar is locatedinside rotor cylinder 33. On the side facing the bearing area 32, thesupport 192 comprises a (second) support plate 194. The two double gearwheels 165 and 175 are arranged on support 192, first double gear wheel165 being supported on an axle pin 168 which is pressed into supportplate 194.

Support 192 is supported on the two freewheel bearings 172 and 173, oneof which blocks in right-handed rotation and the other in left-handedrotation. The bearing 172 is attached to drive shaft 63 which proceedsfrom the step-down gearing 62' and carries the pinion 163. The otherfreewheel bearing 173 is arranged between a power take-off shaft 191 ofsupport 192 and a bearing area of rotor cylinder 33. Support 192 isaccordingly supported at both sides and, depending on rotating directionb, a of drive shaft 63, is connected at a rigid angle either with driveshaft 63 or with rotor cylinder 33.

Grooves on the front side of support plate 194, in which aspring-mounted roller 137 engages, serve to position support 192 atprecisely the right angle.

Disk 185, with its tapered edge 186, and the respective tooth of thedrive wheel 175 together engage in gearing areas 55 to 58 of alladjusting elements 45 to 48 and lock them in their respective positions.The angular position of disk 185 itself is unimportant in this regard.Thus, disk 185 represents a very elegant solution for the aforementionedtertiary means. Alternatively, instead of a planar disk, it is alsopossible to use a cup-shaped element having a cylindrical or conicalwall or other circularly symmetrical form. Other solutions are alsopossible, e.g. in that the adjusting elements 45 to 48 are generallyprovided with a locking position for every stable position.

Drive shaft 63, as shown in FIGS. 4 and 5, is a component part ofstep-down gearing 62' arranged inside rotor cylinder 33, step-downgearing 62' being directly flanged to drive motor 62. Shaft 63 furtherlies in geometrical axis 34 of the rotor cylinder 33.

FIG. 8 shows a variant of the preceding embodiment. In this variant,shaft 63 projects axially and rotatably from rotor cylinder 33 and isdetachably connected with drive motor 62 which is fixed outside rotor33, or with its step-down gearing 62', via an electrically actuatedclutch 91, e.g. a magnetic clutch. Clutch 91 accordingly connects driveshaft 63 with motor 62 only when adjustment is to be carried out. Inparticular, when rotor cylinder 33 rotates the clutch is disengaged. Asubstantial disadvantage of this variant consists in that a controllogic 92 must be provided for controlling the clutch 91, which involvesa substantial expense. It is advantageous that motor 62 is not operatedvia sliding contacts 61 (FIGS. 3 and 5).

The aforementioned disadvantage can be overcome in a very simple manner,corresponding to FIG. 9, by separating motor 62 and assigned step-downgearing 62'. The step-down gearing 62' is arranged inside rotor cylinder33 in such a way that it is rigidly connected with the latter 33. Drivemotor 62 on the other hand is fixed in place outside rotor cylinder 33.Motor 62 and gearing 62' are connected via a connecting shaft 60 whichmay be as long as desired. Connecting shaft 60 is centrally supported inrotor cylinder 33 in a bearing 70.

In order to set the stamps 35 to 38, motor rotor 69 rotates alternatelyin the two rotating directions a, b, as described above, while rotorcylinder 33 remains stationary and in so doing drives, via its shaft 60,the toothed wheels of step-down gearing 62' and finally shaft 63 and theother adjusting means. If on the other hand rotor cylinder 33 isrotating for the purpose of imprinting with the stamps, the adjustingmeans are locked as described, e.g. by means of ball catch elements 136.This locking also acts on the toothed wheels of the step-down gearing62' and the motor rotor 69. The latter 69 therefore rotates togetherwith rotor cylinder 33 relative to stationary motor stator 65, makingexactly one rotation around its own axis. This is a very slow rotationfor motor 62 and is completely unproblematic. The electrical voltageinduced in the motor stator 65 by this rotation can be readilyeliminated electrically, e.g. by means of a resistance short-circuitedto the motor winding.

In this latter variant, the separation line between the parts of rotorunit 25 which rotate along with rotor cylinder 33 and the parts whichare stationary extends between motor rotor 69 and motor stator 65 ofdrive motor 62. This is a natural separation line and is thus veryadvantageous.

FIGS. 8 and 9 further show that rotor cylinder 33 is supported at bothsides via two axles 93, 94 in two U-shaped support legs 95, 96 arrangedfrom above. The surface under the rotor cylinder 33 remains free asbefore in order to allow the passage of letters to be stamped. Thesupport at both sides, however, can have considerable structuraladvantages over the previous conventional support on one side.

In addition to the variants described above, rotor unit 25 allows aconsiderable number of further variants, some of which are mentioned inthe following:

Drive shaft 63 can be arranged centrically relative to rotor axis 34,parallel to it or in any other direction.

The connecting means between drive shaft 63 and adjusting elements 45 to48 can comprise toothed wheels, gear units, axles, etc. as desired.

In conformity with the previous support at one side via the relativelylong shaft 31 (FIG. 5), the spatial separation between motor 62 andstep-down gearing 62' may be considerable. In this case, acorrespondingly long shaft must be used as motor shaft 60, e.g., acardan shaft or a flexible shaft to compensate for parallax errors.

It is further possible to assign a small portion of the step-downgearing 62' directly to motor 62, e.g., a preliminary step-down of 1:2.In this case, the number of rotations of motor rotor 69 increases in acorresponding manner with the rotation of rotor cylinder 33. In everycase, however, the major portion of the step-down gearing 62' should bearranged in rotor cylinder 33.

If motor 62 has a motor shaft 60 which projects out of housing and thestator 65 on both sides, any type of shaft encoder which replaces thearrangement of clock disk 110, intermediate gear 111 and light barrier112 (FIG. 5) can be readily arranged on the side of motor 62 oppositeshaft 67.

Variants with regard to drive motor 62, clutch arrangement 64 and thesupport of rotor cylinder 33 were already mentioned in the preceding. Inparticular, the use of a step motor is possible.

In order to supply power to a drive motor 62 arranged inside rotorcylinder 33 (FIGS. 3 and 5), point form contacts 61 or annular contactsmay be used, as mentioned above. The latter may be arranged orthogonallyor parallel to rotor axis 34. The latter case will result in contactswhich are arranged at the front and can be realized e.g. aswear-resistant mercury contacts.

There are no restrictions as to materials. Therefore, rotor unit 25 maybe made of metal as well as of plastic.

In all the variants described here, stamps 35 to 38 are adjustedserially in a plurality of steps which are continuously monitored. Eachadjusting operation may generally begin from a predetermined zeroposition. This requires a return to this zero position after eachadjusting operation. Alternately, each adjusting operation may beginfrom the end state of the respective preceding adjustment, whichpresupposes continual knowledge of this respective position.

Overall, the advantages of rotor unit 25 are as follows:

It has fewer parts than prior conventional rotor units and isaccordingly less costly to produce.

For the same reason, it can be made smaller, which reduces the moment ofinertia so that rotor drive motor 72 and the bearing 132 can also have aless robust construction, which further reduces the cost. This alsoresults in a saving of space as a whole which can thus be used for otherpurposes.

It does not require a long, unilateral axle as do prior conventionalrotor units; rather, it can be supported in any desired manner,particularly at both sides.

Its construction is electronic to a considerable degree and it istherefore more in keeping with contemporary production trends than priorconventional rotor units.

All stamps 35 to 38 can be adjusted by actuating the keyboard 20 and itis accordingly easy to operate and up to date. Further, every adjustmentmay be externally program-controlled or automated.

Accordingly, rotor unit 25 as a whole forms a very progressive andadvantageous solution for a long-known construction group of postagemeter machines. It can be produced economically and enables easieroperation of the postage meter machine.

While the foregoing description and drawings represent the preferredembodiments of the present invention, it will be obvious to thoseskilled in the art that various changes and modifications may be madetherein without departing from the true spirit and scope of the presentinvention.

We claim:
 1. A rotor unit for a postage meter machine comprising:arotatably supported rotor cylinder; at least one stamp arranged at rotorcylinder, a plurality of adjustable number wheels being assigned to thestamps; setting elements which can be mechanically coupled to the numberwheels and by means of which these wheels can be adjusted according torequirements of a user; a drive shaft which is rotatable in bothdirections (a, b) of rotation and which cooperates with the adjustingelements; a drive motor which drives drive shaft; locking means whichlock all number wheels in their respective position whose setting is notto be changed at the particular time; and connecting means which,depending on the direction (a, b) of rotation of said drive shaft, actin such a way that this drive shaft can be coupled with any desirednumber wheel when rotating in direction (b) and a coupled number wheelcan be brought into a desired setting position when the shaft rotates inthe other rotating direction (a).
 2. A rotor unit according to claim 1,wherein said connecting means comprises at least a freewheel bearing anda shaft, which is supported in said bearing, in such a way that eachfreewheel bearing rigidly locks with the shaft supported in it when thisshaft rotates in a predetermined direction.
 3. A rotor unit according toclaim 2, wherein a single freewheel bearing is provided, and whereinlocking elements are provided, those positions in which the drive shaftare coupled with a number wheel being assigned to the locking positionsof the locking elements.
 4. A rotor unit according to claim 3, whereintwo freewheel bearings are provided, one of which locks with therespective assigned shaft in one rotating direction (b) of said driveshaft, while the other does so in the other rotating direction (a) ofdrive shaft.
 5. A rotor unit according to claim 1, wherein a rotatablysupported disk is provided as the locking means, in that means comprisesa toothed wheel which is arranged at the disk in such a way that alwaysone of its radial teeth completes a part of the disk edge in eachinstance, and wherein intermediate gears engage with the number wheelsand which are circularly arranged in such a way that the edge of thedisk and the respective radial tooth together engage between two teethin each instance in each of the number wheels.
 6. A rotor unit accordingto claim 5, wherein a bearing plate is provided which is arrangedparallel to said disk and is rigidly connected with it, and wherein thefreewheel bearing is arranged on said bearing plate.
 7. A rotoraccording to claim 4 or claim 5, wherein a rotatable support is providedwhich integrally surrounds said disk, and wherein the support is mountedin said two freewheel bearings.
 8. A rotor unit according to claim 1wherein said drive motor can be operated in either of two rotatingdirections, as desired, said motor being controlled by an assignedcontrol unit.
 9. A rotor unit according to claim 8 wherein said drivemotor and an associated step-down gearing are arranged inside said rotorcylinder and are linked with said rotor cylinder, and wherein said driveshaft is the take-off shaft of said step-down gearing.
 10. A rotor unitaccording to claim 8 wherein said drive motor and associated step-downgearing are fixed outside said rotor cylinder, and wherein said driveshaft leads through the wall of rotor cylinder centrically relative tothe axis of the latter, and wherein a controllable clutch is providedwhich is arranged between the gearing and drive shaft.
 11. A rotor unitaccording to claim 1, wherein said drive motor is fixed outside rotorcylinder, wherein associated step-down gearing is arranged in theinterior of said rotor cylinder and is connected with said rotorcylinder, and wherein a connecting shaft is provided which leads throughthe wall of rotor cylinder centrically to its axis and which connectssaid motor rotor of said drive motor and said step-down gearing with oneanother.